Education Secretary Estelle Morris has left her office to tears and applause after she resigned saying the job was too important to have "second best".

In an interview with BBC News Ms Morris said she had "been honest with herself" and thought she had not been as good at the cabinet post as in her old job as schools standards minister.

The former teacher has come under sustained pressure in recent weeks in the wake of the debacle over A-level marking and delays in vetting teachers for the new school year.

I'm not having second best in a job that's as important as this

Estelle Morris

There were further calls for her to quit after she tried to intervene when an appeals panel reinstated two boys expelled for threatening a teacher.

Her departure has prompted speculation about who will replace Ms Morris as secretary of state and has opened up the possibility of a cabinet reshuffle.

Ms Morris was cheered and clapped by civil servants as she left the Department for Education and Skills on Wednesday night.

Several officials even broke down in tears as she walked out.

She was escorted to her car by deputy prime minister John Prescott, who kissed
her on the cheek as she left.

This week the former teacher had faced more trouble over an apparent failure to honour her own promise to resign if education targets were missed.

Tony Blair's official spokesman said the prime minister had "accepted her resignation with regret" and government sources were reported as saying she had not been asked to leave her post.

'Different skills'

Ms Morris said she had felt more comfortable in her previous role as schools minister than as a secretary of state taking big strategic decisions and running a "huge" department.

"If I'm really honest with myself I have not enjoyed it as much and I just do not think I'm as good at it as I was at my other job.

Primary school targets caused the latest row

"I'm not having second best in a job as important as this."

But she denied feeling out-of-her depth and said she was proud of her achievements.

She also said she thought she could justify herself in each of the recent controversies that had hit her tenure.

Ms Morris has endured the full glare of the media spotlight in recent days and admitted she had found that difficult.

"I do not find the modern media and how they relate to politics easy," she continued, explaining it had not been a factor in her resignation.

The outgoing minister said she found some media coverage "intrusive" but said she was not critical of journalists.

Blair talks

In her resignation letter to Mr Blair, Ms Morris said: "All this has meant that with some of the recent situations I have been involved in I have not felt I have been as effective as I should be or as effective as you need me to be."

Mr Blair met Ms Morris on Tuesday to discuss her wish to resign and he told her to think about it overnight.

She said she had done that and was "absolutely sure" she wanted to go.

A-level marking raised the pressure on Morris

In a letter to Ms Morris, the prime minister said he was certain she would return to government.

"I have no doubt you are doing an excellent job, as I said to you and I have full confidence in you," said Mr Blair.